The present invention relates to control of the configuration of supporting beams, particularly beams which are subject to deformation due to nonuniform heating.
The present invention was developed particularly for use in the paper making art where horizontally oriented structural beams support scanning sensor-supporting carriages which travel transversely to a paper sheet in order to monitor one or more characteristics of that sheet across its width, such as basis weight (i.e., the mass per unit surface area of the sheet).
Paper sheet is manufactured at elevated temperatures. Thus, the portion of the beam nearest to the paper sheet may be heated by infrared radiation and convection from the sheet. In such installations, since the support beams are subjected to nonuniform heating transverse to their length, this nonuniform heating will cause the beam to bend so that the scanning sensors no longer traverse a linear path. Particularly when bending occurs in a vertical direction, the distance between the sensors and the paper sheet will vary across the width of the sheet, resulting in falsified readings.
Attempts to prevent such beam deformations by additional mechanical supports have met with only limited success in view of the large forces generated by uneven heating.